1. Field of the Invention
The present invention relates to an image pick-up apparatus and an image pick-up method that enable to obtain a slow synchronized image using a plurality of image sensors.
2. Description of the Related Art
In recent years, owing to camera shake compensation and improvement of auto focus of a digital camera, even a beginner causes a substantially lower risk of picking up a camera-shaken image or a blurred image. This is because from demands by general users, the camera makers have made efforts on improvement of the cameras. However, some people who have interests in photographing demand to actively generate motion blur to express movements of an object or to obtain an image in which a motion-blurred image and an motionless image (non-motion-blurred image) appearing that the movement stops for a moment during the movement, co-exist. A shooting procedure of “slow synchronized flash” is a method to pick up such an image. In this method, an image is picked up while flash is being emitted to a moving object only for a short time. Thereby, in that image, the moving object appears to be motionless only in a moment the flash is being emitted while the object is taken motion-blurry. Since a time period when the flash is emitted is shorter than a shutter speed and a light amount is large, the motion-blur of the object stops only when the flash is emitted and the object is motion-blurred for the rest of time in the obtained image. The shutter speed is set to a slow shutter of about 1/15 seconds so that a motion-blur of the object can be intentionally generated. The image obtained as such becomes dynamic, in which a motion-blurred image of a moving object and a motionless image of the object stopping its movement for a moment, co-exist.
A pick-up method using a plurality of image sensors includes a method for enlarging a dynamic range (Japanese Patent Application Laid-Open No. 7-131799). This invention aim to enlarge a dynamic range compared to an image picked up by one image sensor, by picking up image signals at different shutter speeds by the plurality of image sensors and combining the image signals.